The invention discloses a riveting force-based aircraft pneumatic riveting process online monitoring method and system, so as to evaluate the quality of the riveting process. Firstly, riveting force signals at a riveting part are acquired continuously; the peak signal of the riveting force signals is then recognized; the peak amplitude of the peak signal, the peak position and the instantaneous frequency of the peak signal are recorded; the acquired signals of the whole riveting process are sequentially divided to a pretension stage, a transition stage, a molding stage and a release stage according to a time sequence; the effective riveting force during the actual riveting process is compared with a standard riveting force of a standard riveting process finally; or, a pier head height during the actual riveting process is compared with a pier head equivalent height during the corresponding standard riveting process. A reference riveting process is also provided, and based on the reference riveting process, the actual riveting process is evaluated. The method disclosed in the invention can provide a quantitative comparison basis for different riveting processes, the applicability isstrong and the maneuverability is high. Theoretical guidance can be provided for riveting training and riveting process quality control.